1. Field of the Invention
This invention relates to a towing apparatus for motorized vehicles. More particularly it relates to a towing apparatus having a single wheel design to be towed behind a motorcycle or recreational vehicle.
2. Description of the Prior Art
In motorized vehicles, such as two or three-wheeled motorcycles and recreational vehicles, it is desirable to have a trailer assembly which is compact in size and light in weight. Motorcycles and recreational vehicles are typically powered by small displacement engines having four or fewer cylinders. In addition, motorcycles and recreational vehicles typically have small total vehicle weights. Thus a motorcycle towing apparatus must be compatible in weight to provide for easy and efficient towing behind the motorcycle or recreational vehicle. Towing a trailer with a motorcycle or recreational vehicle may increase the risk of injury to an operator or a passenger. Hitting an obstruction on the road surface with a wheel of the motorcycle or trailer may cause the two or three wheeled motorcycle to lose control. Thus it is desirable to provide a motorcycle towing apparatus which enhances operator and passenger safety by minimizing the risk of hitting an obstruction on the road surface by minimizing the "footprint" of the combination of the motorcycle or recreational vehicle and trailer wheels on the road surface. It is also desirable to enhance operator and passenger safety by providing a motorcycle towing apparatus having handling characteristics compatible with the two-wheeled motorcycle design.
In the past, towing apparatus for motorcycles and recreational vehicles have utilized designs incorporating two wheels. Typically these designs are derived from applications within the automotive industry and may not accommodate the particular needs of two and three-wheeled motorcycles. First, the two-wheeled design inherently provides two wheels which do not "ride" the same track as the front and rear wheels of the two-wheeled and three-wheeled motorcycles. For example, the three-wheeled motorcycle has a "footprint" of three wheels on the road surface. If the three-wheeled motorcycle is towing a trailer which has two wheels, the total "footprint" of five wheels on the road surface may make it unsafe to operate the three-wheeled motorcycle. If an obstruction is on the road surface, it may be difficult to avoid that obstruction with a "footprint" of five wheels thus subjecting the operator and passenger to an enhanced risk of injury. Although two-wheeled motorcycle designs towing a two-wheeled trailer have a "footprint" of three wheels, thus making it easier to avoid an obstruction on the road surface, the operator and passenger still have an enhanced risk of injury due to a possibility of tipping over. Another problem of towing the two-wheeled trailer is that while the operator may easily look forward and concentrate on keeping the front and rear wheel of a motorcycle out of an obstruction related to a road hazard, it is not easy to do the same with the two trailer wheels since the trailer wheels are behind the line of vision of the operator. Unfortunately, injury to the motorcycle operator or passenger may result if one or both of the two trailer wheels comes into contact with the obstruction.
Another problem is that the two-wheeled trailer does not have handling characteristics compatible with the two-wheeled motorcycle design. Typically the two-wheeled motorcycle negotiates a turn by steering the motorcycle to initiate a weight shifting in order to lean the motorcycle into the turn. Unfortunately, the two-wheeled trailer design is not compatible with the two-wheel motorcycle design as it does not similarly lean thus making it more difficult for the motorcycle operator to safely predict the handling of the trailer. In addition, the ball and hitch assembly typically used to couple the trailer to the motorcycle may limit the amount of lean of the motorcycle relative to the trailer.
In one approach in the prior art, a one-wheeled trailer design is coupled to the vehicle via two hingeable support arms where the one wheel trailer follows the vehicle by a castering type action. While this approach does provide the advantage of minimizing the footprint of the motorcycle and trailer combination, it has at least two disadvantages. First, since two hingible supports are utilized to couple the trailer to the motorcycle, a pendulum effect is created tending to shift the back end of the vehicle to the outside of the turning radius resulting in a loss of control of the motorcycle. Second, the single castor-type wheel is subject to higher vibration due to the side-to-side motion possible with the castor design. This additional vibration may cause operator or passenger discomfort, or worse, may cause loss of control of the motorcycle if severe enough.